Heat sink, liquid cooling unit, and electronic apparatus

ABSTRACT

A heat sink for absorbing heat which is generated by an electronic module by a coolant which flows through its internal portion, provided with a first heat sink part which is contiguous with the electronic module, a second heat sink part which is contiguous with the electronic module, and a heat discharger which is arranged spaced from the first heat sink part and second heat sink part at an opposite side from the electronic module and which is arranged in a flow path between the first heat sink part and second heat sink part.

CROSS REFERENCE TO RELATED APPLICATION

This application claims priority of Japan Patent Application Number 2010-196526, filed on Sep. 2, 2010.

FIELD

The present invention relates to a heat sink for absorbing heat which is generated by an electronic module and a liquid cooling unit and an electronic apparatus which are provided with a heat sink.

BACKGROUND

Notebook personal computers and other electronic apparatuses have printed circuit boards installed therein. On the printed circuit boards, for example, LSI (large scale integrated circuit) chips and other electronic modules are mounted. In order to absorb heat which is generated by these electronic modules, a liquid cooling unit provided with a heat sink is disposed on the printed circuit board.

As related art, Japanese Laid-Open Patent Publication No. 2005-229033 is known.

When providing a liquid cooling unit at a notebook personal computer or other electronic apparatus, due to the design of the internal layout of the electronic apparatus, the space where the liquid cooling unit can be provided is sometimes limited. In general, as the area of the heat sink of the liquid cooling unit becomes smaller, the liquid cooling unit falls in cooling efficiency. Therefore, when the area of the part where the heat sink can be provided is limited, it is not possible to sufficiently raise the cooling efficiency of the liquid cooling unit.

SUMMARY

Accordingly, it is an object of the embodiment to provide a heat sink which improves the cooling efficiency over the related art, when the area of the part where the heat sink of the liquid cooling unit can be provided is limited.

According to a first aspect, there is provided a heat sink for absorbing heat which is generated by an electronic module by a coolant which flows through its internal portion, comprising a first heat sink part which is contiguous with the electronic module, a second heat sink part which is contiguous with the electronic module, and a heat discharger which is arranged spaced from the first heat sink part and second heat sink part at an opposite side from the electronic module and which is arranged in a flow path between the first heat sink part and second heat sink part.

Further, according to a second aspect, there is provided a liquid cooling unit which is provided with the above heat sink.

Furthermore, according to a third aspect, there is provided an electronic apparatus which is provided with the above heat sink.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view which illustrates an example of a notebook PC of a first embodiment.

FIG. 2 is a perspective view which illustrates an example of the structure of an internal portion of a housing body of the first embodiment.

FIG. 3 is a plan view which illustrates an example of a liquid cooling unit according to the first embodiment.

FIG. 4 is a perspective view which illustrates an example of a heat sink according to the first embodiment.

FIG. 5 is a perspective cross-sectional view which illustrates an example of a heat sink according to the first embodiment.

FIG. 6 is a perspective view which illustrates a modification of a heat sink according to the first embodiment.

FIG. 7A is a perspective view which illustrates an example of a heat sink according to a second embodiment, while FIG. 7B is a cross-sectional view taken along the line A-A in FIG. 7A.

FIG. 8A is a perspective view which illustrates an example of a heat sink according to a third embodiment, while FIG. 8B is a cross-sectional view seen from the arrow direction in FIG. 8A.

FIG. 9 is a perspective view which illustrates an example of a heat sink according to a fourth embodiment.

DESCRIPTION OF EMBODIMENTS

According to the heat sink of the disclosure, by provision of a heat discharger, the cooling efficiency can be improved to more than that of the related art.

(1) First Embodiment

First, with reference to FIG. 1, a notebook personal computer (notebook PC) 10 will be explained as an example of an electronic apparatus based on a first embodiment. FIG. 1 is a perspective view which illustrates an example of the notebook PC 10 according to the first embodiment. As illustrated in FIG. 1, the notebook PC 10 is provided with a housing body 20 and a display use housing 30. The display use housing 30 is coupled with the housing body 20 so that opening/closing is possible.

The housing body 20 is provided with a base 22 and a cover 24. The cover 24 can be detached from the base 22. Further, on the surface of the cover 24, a keyboard 26, a pointing device 28, and other input devices are disposed.

The display use housing 30 is provided with a liquid crystal panel module 32. The liquid crystal panel module 32 displays text, graphics, etc.

Next, with reference to FIG. 2, the structure of the internal portion of the housing body 20 will be explained. FIG. 2 is a perspective view which illustrates an example of the structure of the internal portion of the housing body 20 of the first embodiment. As illustrated in FIG. 2, the housing body 20 of the first embodiment is provided with a printed circuit board unit 40, a DVD (digital versatile disk) drive device 46, a hard disk drive device 48, a card unit 50, and a liquid cooling unit 100.

The printed circuit board unit 40 is provided with a printed circuit board 42 and an electronic module 44. The electronic module 44 is mounted on, the surface of the printed circuit board 42. The electronic module 44 is for example an LSI circuit. On the LSI circuit or other electronic module 44, for example, a CPU (central processing unit) chip is mounted. The CPU chip executes predetermined processing based on an operating system and application programs. When the CPU chip executes the processing, the LSI circuit or other electronic module 44 generates heat.

In order to absorb the heat generated by the electronic module 44, a liquid cooling unit 100 is attached to the printed circuit board unit 40. The detailed configuration of the liquid cooling unit 100 will be explained later.

The DVD drive device 46 reads data from a DVD or other recording medium and writes data to the DVD or other recording medium. The hard disk drive device 48 stores for example the operating system and application software explained above.

Further, the card unit 50 is mounted on the printed circuit board 42. Into the card unit 50, for example, a memory card or LAN (local area network) card is inserted.

Here, with reference to FIG. 3, the liquid cooling unit 100 of the first embodiment will be explained. FIG. 3 is a plan view which illustrates an example of the liquid cooling unit 100 according to the first embodiment. As illustrated in FIG. 3, the liquid cooling unit 100 of the first embodiment is provided with a heat exchanger 110, fan unit 120, tank 130, pump 140, and heat sink 150. Members configuring the liquid cooling unit 100 are connected by a plurality of hoses 102 and a plurality of joints 104 to form a circulation route. By the coolant which flows over this circulation route, the heat generated by the electronic module 44 is discharged to the outside of the notebook PC 10. As the coolant, use is made of, for example, a propylene glycol-based antifreeze.

The heat exchanger 110 takes the heat from the coolant which flows into the heat exchanger 110. The heat exchanger 110 is disposed in the vicinity of an exhaust port 52 (see FIG. 2) formed at the side surface of the housing body 20. Further, the fan unit 120 is disposed in the vicinity of the heat exchanger 110. The fan unit 120 generates an air flow from the heat exchanger 100 toward the exhaust port 52. For this reason, the heat taken from the coolant by the liquid cooling unit 100 is discharged through the exhaust port 52 to the outside of the notebook PC 10.

The fan unit 120 is provided with a fan housing 122 and a fan 126. On the bottom plate and top plate of the fan housing 122, an air intake opening 124 is formed. The air intake opening 124 connects the internal space of the fan housing 122 and the outside space of the fan housing 122.

The tank 130 is disposed downstream of the heat exchanger 110. The tank 130 stores the coolant stripped of heat by the heat exchanger 110.

The pump 140 is disposed downstream of the tank 130. The pump 140 discharges the coolant stored in the tank 130 to generate the flow of the coolant which flows over the circulation route. The pump 140 is for example a piezoelectric pump.

The heat sink 150 is disposed downstream of the pump 140. As illustrated in FIG. 2, the heat sink 150 is disposed above the electronic module 144 which generates heat. The heat sink 150 absorbs the heat generated by the electronic module 44. The detailed configuration of the heat sink 150 will be explained later.

The heat exchanger 110 explained above is located downstream of the heat sink 150. In the liquid cooling unit 100, a circulation route as explained above is formed.

Next, the structure of the heat sink 150 of the first embodiment will be explained in detail with reference to FIG. 4 and FIG. 5. FIG. 4 is a perspective view which illustrates one example of the heat sink 150 according to the first embodiment. The arrows in FIG. 4 illustrate the flow of the coolant which flows through the heat sink 150. FIG. 5 is a perspective cross-sectional view which illustrates one example of the heat sink 150 according to the first embodiment.

As illustrated in FIG. 4, the heat sink 150 of the first embodiment is provided with a first heat sink part 152, a second heat sink part 154, and a heat discharger 156. The second heat sink part 154 is arranged aligned with the first heat sink part 152. Further, in the first embodiment, the first heat sink part 152 and the second heat sink part 154 are both contiguous with the same surface of the electronic module 44. Note that the first heat sink part 152, the second heat sink part 154, and the electronic module 44 may also have heat conductive grease interposed between them.

At the two ends of the first heat sink part 152, flow pipes 170 and 172 are provided. Further, at the two ends of the second heat sink part 154, flow pipes 174 and 176 are provided. Further, the flow pipes 172 and 174 are connected by the heat discharger 156.

Here, referring to FIG. 5, the structure of the interior part of the heat sink 150 will be explained. As illustrated in FIG. 5, the first heat sink part 152 and the second heat sink part 154 are partitioned by a partition plate 155. Further, the first heat sink part 152, the second heat sink part 154, and the heat discharger 156 are provided, inside them, with fins 158. In the example illustrated in FIG. 5, the first heat sink part 152, the second heat sink part 154, and the heat discharger 156 are each provided with nine fins 158 along the direction of flow of coolant. The fins 158 are, for example, formed by aluminum or another metal material with a high heat conductivity. For this reason, the heat which the electronic module 44 generates is conveyed to both the housings and fins 158 which form the first heat sink part 152 and the second heat sink part 154 and the heat is absorbed by the coolant.

The heat discharger 156 is arranged spaced from the first heat sink part 152 and the second heat sink part 154, at the opposite side from the electronic module 44. Further, the heat discharger 156 is arranged in the flow path between the first heat sink part 152 and the second heat sink part 154. For this reason, as illustrated by the arrows in FIG. 4, the coolant, which flows in from the joint 104 to the heat sink 150, passes through the flow pipe 170, the first heat sink part 152, the flow pipe 172, the heat discharger 156, the flow pipe 174, the second heat sink part 154, and the flow pipe 176 and flows out from the heat sink 150.

Here, the action of the heat which is generated by the electronic module 44 being absorbed by the heat sink 150 of the first embodiment will be explained. First, the coolant, which flows into the heat sink 150, passes through the flow pipe 170 and flows through the first heat sink part 152. Part of the heat which is generated by the electronic module 44 is conducted to the housing of the first heat sink part 152 and the fins 158 and is absorbed by the coolant which flows through the first heat sink part 152. Therefore, the temperature of the coolant which flows through the first heat sink part 152 rises. The coolant, which flows through the first heat sink part 152 and rises in temperature, passes through the flow pipe 172 and flows through the heat discharger 156. The heat discharger 156 is arranged spaced from the first heat sink part 152 and second heat sink part 154, so the temperature of the coolant which flows through the heat discharger 156 falls. The coolant, which flows through the heat discharger 156 and falls in temperature, passes through the flow pipe 174 and flows through the second heat sink part 154. Part of the heat which is generated by the electronic module 44 is conducted to the housing of the second heat sink part 154 and the fins 158 and is absorbed by the coolant which flows through the second heat sink part 154. The coolant which flows through the second heat sink part 154 passes through the flow pipe 176 and flows out to the outside of the heat sink 150.

Therefore, according to the heat sink 150 of the first embodiment, since the coolant which was lowered in temperature by flowing through the heat discharger 156 flows through the second heat sink part 154, the cooling efficiency of the heat sink 150 can be improved. Further, the heat discharger 156 of the first embodiment is arranged spaced from the first heat sink 152 and second heat sink 154 at an opposite side from the electronic module 44, so even when the area of the part where the heat sink 150 can be provided is limited when viewed from a plane, the cooling efficiency of the heat sink 150 can be improved.

Note that, inside of the housing body 20 which was explained with reference to FIG. 2, an air flow is formed by the fan unit 120. Due to the air flow through the inside of the housing body 20, the coolant, which flows through the heat discharger 156, is cooled more efficiently, so the heat sink 150 is preferably arranged in the vicinity of the fan unit 120.

Further, the larger the area of the heat discharger 156, the more improved the cooling efficiency of the coolant which flows through the heat discharger 156. Therefore, like in the example illustrated in FIG. 4, the heat discharger 156 is preferably arranged at a slant with respect to the first heat sink 152 and the second heat sink 154 which are arranged aligned with each other.

Note that in the above embodiment, the example was explained of the heat sink 150 being provided with a single heat discharger 156, but the heat sink 150 may also be provided with a plurality of heat dischargers 156. Here, referring to FIG. 6, an example where the heat sink 150 is provided with a plurality of heat dischargers 156 will be explained. FIG. 6 is a perspective view which illustrates an example where the heat sink 150 is provided with two heat dischargers 156. In the example which is illustrated in FIG. 6, the two heat dischargers 156 are arranged spaced from the first heat sink part 152 and the second heat sink part 154 at an opposite side from the electronic module 44.

When, as in the example which is illustrated in FIG. 6, the heat sink 150 is provided with two heat dischargers 156, the cooling efficiency of the coolant which flows through the heat discharger 156 is improved compared with the case where the heat sink 150 is provided with one heat discharger 156.

(2) Second Embodiment

Next, a second embodiment will be explained. The second embodiment differs in the configuration of the heat sink 150 from that of the first embodiment. The rest of the configuration is similar to that of the first embodiment, so an explanation will be omitted. Below, the configuration of the heat sink 150 of the second embodiment will be explained with reference to FIGS. 7A and 7B. FIG. 7A is a perspective view which illustrates an example of the heat sink 150 of the second embodiment, while FIG. 7B is a cross-sectional view taken along a line A-A in FIG. 7A.

As illustrated in FIG. 7A, the heat discharger 156 of the second embodiment is shaped as a parallel hexagon. Further, as illustrated in FIG. 7B, the normal of the surface with the largest area in the surfaces of the heat discharger 156 is slanted with respect to the normal of the surface with the largest area in the surfaces of the first heat sink part 152. That is, the surface with the largest area in the surfaces of the heat discharger 156 is slanted with respect to the surface with the largest area in the surfaces of the first heat sink part 152.

In the example illustrated in FIGS. 7A and 7B, the heat discharger 156 is provided so that the surface with the largest area in the surfaces of the heat discharger 156 is slanted with respect to the surface with the largest area in the surfaces of the first heat sink part 152. Therefore, compared with the case, like in the first embodiment which was explained with reference to FIG. 4, where the surface with the largest area in the surfaces of the heat discharger 156 is parallel with respect to the surface with the largest area in the surfaces of the first heat sink part 152, in the second embodiment, it is possible to increase the surface area of the heat discharger 156. As a result, the cooling efficiency of the coolant which flows through the heat discharger 156 is improved.

Further, by providing the heat discharger 156 so that the surface with the largest area in the surfaces of the heat discharger 156 is slanted with respect to the surface with the largest area in the surfaces of the first heat sink part 152, the flow of air through the inside of the housing body 20 touches the surface of the heat discharger 156 more efficiently than the first embodiment. Therefore, the cooling efficiency of the coolant which flows through the heat discharger 156 is improved.

(3) Third Embodiment

Next, a third embodiment will be explained. The third embodiment differs in the configuration of the heat sink 150 from that of the first embodiment. The rest of the configuration is similar to that of the first embodiment, so an explanation will be omitted. Below, the configuration of the heat sink 150 of the third embodiment will be explained with reference to FIGS. 8A and 8B. FIG. 8A is a plan view which illustrates an example of the heat sink 150 according to the third embodiment, while FIG. 8B is a front view seen from the arrow B direction of FIG. 8A.

As illustrated in FIGS. 8A and 8B, the heat sink 150 of the third embodiment is provided with fins 160 between the first heat sink part 152 and the heat discharger 156 or between the second heat sink part 154 and the heat discharger 156. In the example illustrated in FIG. 8A, five fins 160 are provided along the direction of flow of the coolant inside of the heat discharger 156.

In the third embodiment, the heat generated by the electronic module 44 is conducted to both the housings and fins 160 forming the first heat sink part 152 and the second heat sink part 154. In addition to the effects of the above embodiments, heat is discharged from the fins 160 as well. Therefore, according to the third embodiment, the cooling efficiency of the heat sink 150 can be further improved.

(4) Fourth Embodiment

Next, a fourth embodiment will be explained. The fourth embodiment differs in the configuration of the heat sink 150 from that of the first embodiment. The rest of the configuration is similar to that of the first embodiment, so an explanation will be omitted. Below, the configuration of the heat sink 150 of the fourth embodiment will be explained with reference to FIG. 9. FIG. 9 is a perspective view which illustrates an example of the heat sink 150 according to the fourth embodiment. The arrows in FIG. 9 illustrates the flow of the coolant through the heat sink 150

As illustrated in FIG. 9, the heat sink 150 of the fourth embodiment is provided with a first heat sink part 152, a second heat sink part 154, a third heat sink part 162, a heat discharger 156, and an additional heat discharger 164. The first heat sink part 152, the second heat sink part 154, and the third heat sink part 162 are arranged adjoining each other while aligned, but respectively independent flow paths are formed inside them. The contiguous parts of the above members are not internally communicated. Further, the first heat sink part 152, the second heat sink part 154, and the third heat sink part 162 are all contiguous with the electronic module 44.

At the two ends of the first heat sink part 152, flow pipes 180 and 182 are provided. Further, at the two ends of the second heat sink part 154, flow pipes 184 and 188 are provided. Further, at the two ends of the third heat sink part 162, flow pipes 186 and 188 are provided. Further, the flow pipes 182 and 184 are connected by the heat discharger 156. Further, the flow pipes 182 and 186 are connected by the additional heat discharger 164.

The structure of the interior part of the third heat sink part 162 is similar to the structure of the interior part of the first heat sink part 152 explained in the above first embodiment. Further, the structure of the interior part of the additional heat discharger 164 is similar to the structure of the interior part of the heat discharger 156 explained in the above first embodiment.

In the same way as the above embodiments, the heat discharger 156 is arranged spaced from the first heat sink part 152 and the second heat sink part 154 at the opposite side from the electronic module 44. The additional heat discharger 164 is arranged spaced from the first heat sink part 152 and third heat sink part 162 at the opposite side from the electronic module 44.

Further, in the same way as the above embodiments, the heat discharger 156 is arranged in the flow path between the first heat sink part 152 and the second heat sink part 154. The additional heat discharger 164 is arranged in the flow path between the first heat sink part 152 and the third heat sink part 162.

Therefore, as illustrated by the arrows in FIG. 9, the coolant which flows into the heat sink 150 passes through the flow pipe 180, the first heat sink part 152, the flow pipe 182, the heat discharger 156, the flow pipe 184, the second heat sink part 154, and the flow pipe 188 and flows out from the heat sink 150 and, at the same time, the coolant passes through the flow pipe 180, the first heat sink part 152, the flow pipe 182, the additional heat discharger 164, the flow pipe 186, the third heat sink part 162, and the flow pipe 188 and flows out from the heat sink 150.

In the fourth embodiment, the coolant which flows through the first heat sink part 152 is cooled by flowing into both the heat discharger 156 and the additional heat discharger 164, so the cooling efficiency of the heat sink 150 can be further improved.

A detailed explanation was given above on the heat sink, liquid cooling unit, and electronic apparatus of the present invention, but the present invention is not limited to the above-described embodiments. Further, the embodiments explained above may be suitably combined. Further, various modifications and alterations may be made within the scope of the present invention.

All examples and conditional language recited therein are intended for pedagogical purpose to aid the reader in understanding the invention. 

What is claimed is:
 1. A heat sink for absorbing heat generated by an electronic module by a coolant flowing through its internal portion, comprising: a first heat sink part which is contiguous with said electronic module; a second heat sink part which is contiguous with said electronic module; and a heat discharger which is arranged spaced from the first heat sink part and second heat sink part at an opposite side from said electronic module and which is arranged in a flow path between the first heat sink part and second heat sink part.
 2. The heat sink according to claim 1, comprising a plurality of said heat dischargers.
 3. The heat sink according to claim 1, wherein the surface with the largest area in the surfaces of the heat discharger is slanted with respect to the surface with the largest area in the surfaces of said first heat sink part.
 4. The heat sink according to claim 1, further comprising fins between said first heat sink part and said heat discharger and/or between said second heat sink part and said heat discharger.
 5. The heat sink according to claim 1, further comprising a third heat sink part which is arranged aligned with said first heat sink part and second heat sink part and which is contiguous with said electronic module and an additional heat discharger which is arranged spaced apart from said first heat sink part and said third heat sink part at an opposite side from said electronic module and which is arranged in a flow path between the first heat sink part and third heat sink part.
 6. A liquid cooling unit comprising a heat sink for absorbing heat which is generated by an electronic module by a coolant flowing through its internal portion, a heat exchanger of the coolant, and a pump which circulates said coolant, wherein said heat sink comprising a first heat sink part which is contiguous with said electronic module, a second heat sink part which is contiguous with said electronic module, and a heat discharger which is arranged spaced from the first heat sink part and second heat sink part at an opposite side from said electronic module and which is arranged in a flow path between the first heat sink part and second heat sink part.
 7. An electronic apparatus comprising an electronic module which generates heat, a heat sink for absorbing heat which is generated by said electronic module by a coolant which flows through its internal portion, and a pump which circulates said coolant, wherein said heat sink is comprised of a first heat sink part which is contiguous with said electronic module, a second heat sink part which is contiguous with said electronic module, and a heat discharger which is arranged spaced from the first heat sink part and second heat sink part at an opposite side from said electronic module and which is arranged in a flow path between the first heat sink part and second heat sink part. 